The small (ca. 1”x1”) piece of lead-cerium glass
pictured on the right was charged by exposing it for 20 seconds to a 10µA
current of 1.5 MeV electrons from an accelerator at Oak Ridge National
Laboratory. When the block of glass was discharged, a time-lapse photograph
was taken of the “tree of fire.”

The photograph was so striking that it was used on
the cover of the
March 2, 1962
issue of Science.